I expect that his Galaxy 8 came with a cable and that son (or you) want a backup for. Is it a USB-C port/cable? If so, I've heard that "low quality" USB-C cables can damage a motherboard. I'd recommend that he spend the $$$ and purchase a Samsung branded cable. That way, should something go wrong, Samsung can't blame "the cheap cable" you used.

I had just purchased a number of micro-usb cables to use with my Note 5. I found some good quality cables on Amazon. Mainly, I wanted longer cables, so I purchased a couple of 10 footers and at least half a dozen 6 footers.

Next thing I know, I got a great offer from Verizon on a Note 8. I solved my dilemma by buying "c" adapters and they are working just fine.

Just make sure the cables are rated for fast charging/quick charging plus at least 3A, and have lots of 5 star reviews, and are of course the desired length and color that you want. IOW, stay away from poor quality cables, and if you have any concerns, use a low amp adapter... but w/ cables being affordable, just stick w/ good ones.
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